SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b2612e81348044328fe96d316337912294accfaead88696df1ea40402f764e' 
  AND token = 'kAz7XNTs4yK9f7X7WueaD9AHzZ+b3NVFQ86s90k7HlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}