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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4564fa6b3bf17fba7dfb1eaa8cf1232f06e09434a2ae27a478a08c24da622a5' 
  AND token = 'LE5Tdbfd9pvE+nFS1+4zaCZcRqgrtWfN9xpPaBLfFhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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