SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6fedf1183e795b401e9772d022dc51c55394c18913fb9ad834612217e6793d3' 
  AND token = 'J6A7vCf2wly4Qws0mYYTax07tFH39QFtAJX2lLiPsrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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