SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca501649dd22928acf6bd71229f7c08b7aebe730bfd4ce52f0b7eb7d89c5c5db' 
  AND token = 'R/BGYVeiUeqfLlYyrSyo4Z2IJj01dGT3+GC1Oi/hUNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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