SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89ce7903bc193651a9cad2517039840469d4c82ebde9122281e47d884ec63692' 
  AND token = 'rzhVPEqhCTKQnFt0CFaxJPWIZklfXTaFN2cVIsA7PLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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