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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ecef96daca0e6c970c7bcc4a06f26d446c90728fe4bb28c8fa1af09b1ece3c3' 
  AND token = 'mgr3GLtYAB+PkmHXf2A23c715BJmmO6s4T21FrwulIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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