SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7747a0e4c1c28a25e6cf96036dd1a97ed5db9f8b4c524098dc8c09c4265127f4' 
  AND token = 'MhbLDxWEy0zZxB/YPGkaujg0uhvRM7h5wGYxN6CDuKk=' 
  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"
    }
  }
}