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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e437a207b189694fb60bb9fb0dbaaba0e01a6446be290064da50bdbaaa1c0e08' 
  AND token = 'WP7xjUvFoNzSOoVuqDAt3sf5fc+sa6w7bwKcL3HfHPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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