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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ba2ca4e9772d0f03fea06bd75ffb67a412a1261d8ea8c51ebd5fd51f1f74a73' 
  AND token = 'jWz/dEuzsZ/Pq9Oh4DkD7QS5sFqX2llPT9CAwfTaaTs=' 
  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"
    }
  }
}