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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f37de4dee58ebb39a6b381cce7fde98d0127261dfd7a913b94e318063d9d9c2' 
  AND token = 'BvDgVnaS8wwALoQv9FEW06YVOkxDe+Wv4x4Os7SXhWg=' 
  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"
    }
  }
}