SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b5964d8c5e56c7d0fd110d6020f20c92a35c748da20b356d02c77f3343b3ee8' 
  AND token = 'D99vnZflFVxxX1rDUQbYZ74R6EfHCrhfVj+TOKjQKWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}