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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b4fb5207f1fd6b5250c31d01b3c9866d52ee5bd9eb78ed98b4686d0ff469680' 
  AND token = 'mtd/4sgi4Yqr+rXAgAoQjMZpA6A0OD1G8Exi6Wy85cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}