SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69a8526eb17c64ac373608dfcb0a8ad236ea3b3c6cbe9653443bbe1118ec6ff6' 
  AND token = 'qHaSTaMkI1D5HRL7bdz4LO5SpPSiZzmvGU7+LNAp0eI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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