SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '858676307e70b5c3604493fb25e36303f67ff973548cb75d04ac7b24e92dc1d5' 
  AND token = '1NvfP2DJGvrSCunwb12Lh8/xa+di/OuBa9Iz9L4+UJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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