SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9738535faf9945eab727dd7aac06cc0e62559c5a34ce605666aba3c38e69c89f' 
  AND token = 'ud3WBlRy3ueVSGLoztGOPLNedKL2INgcYITYV8ILn5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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