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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '486c961fa848444b0daa67396c1064c37f424549fbfd9c11aac3c8f717b424a0' 
  AND token = 'rnuEzRJ6yemkoDcOXTmbSM5/pVJ9RYJcJFc1B4oxlMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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