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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c7f0b1de2b3d52f199cdb05a28e500d640c3eb3b714c7d84595df1b514b230b' 
  AND token = 'J5q3fVFJBHC+kS6zXuRJM5Lu/H8bOE9h8wQ1ElBGIu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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