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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fea9a20ec9ff82e00551d46967c972a7fade4d93631d9658f217dff9e9aa6b27' 
  AND token = 'ZM+YS4iL1A6n7sCAbT6ZdR9/bRNwSVz7lRSSPYlFO7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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