SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0f9a87993728a167ecd6fb162e6304c4594a7869276bc5aed17e8db4f38da8a' 
  AND token = 'HbBiv5eVSaCFtJ1e4TXlp75r4rBH7e/GlfxL5Jr+/Wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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