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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76f52c394f8bc8fe57d96577f7fc1cf8d53b9ebfb30267e0ab5dfbb77c15efad' 
  AND token = 'cG6DdrjhI3Yrizy9R4rj6RZCe+Cf+AQsb69Y1qNwx8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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