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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee5e2c58601bf703ffd8ad9f24f5aa9a2511203b9ee6dea2732c364ec4e6d421' 
  AND token = 'HkHsF1Ta+/jdShEguQWILxt/qwwj1ztd7navr+ovDEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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